Cooling system for electron tubes and other devices



April 15, 1952 E. BROWN COOLING SYSTEM FOR ELECTRON TUBES AND OTHER DEVICES- Filed Oct. 12, 1946 3&1

CONTROL n a 6mm ,47. a

;*=jeii=j=fiiajt: w I 1 1 l 14 I6 .5 m as as m 4 za as a; a: as a4 56 j a5 1: m 39 A I I I 50 n n 4 r I I 5 Patented Apr. 15, 1952.

COOLING SYSTEM FOR ELECTRON TUBES AND OTHER DEVICES William E. Brown, Pewaukee, Wis., assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application October 12, 1946, Serial No. 703.090

4 Claims. 1

This invention relates to fluid cooling systems for electron tubes and other devices, and more particularly to an improved protective means which detects and responds to abnormalities of coolant flow.

In the application of N. R. Juech, Serial No. 701,334., filed October 4, 1946, now abandoned, there is disclosed a protective means which responds to coolant flow rate abnormalities. The protective means disclosed therein embodies the use of a Venturi device which responds in a direct relation to coolant flow rate. However, that means does not afford protection against temperature abnormalities of the flowin coolant.

An object of the invention is to provide a protective means which is responsive to both temperature and flow rate abnormalities in a cooling system. I

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate the invention in detail and show a schematic embodiment of the same in a cooling system, it being understood that the details and embodiment illustrated may be modified in various ways without departing from the scope of the appended claims.

In the drawings,

Figure 1 is a schematic showing of an improved protective means, whichembodies the invention, in its working relation to a coolant conducting system for an electronic tube, and

Fig. 2 is a detailed showing of certain means shown in Fig. 1.

Referring to Fig. 1, it shows an electron tube I, and protective means therefor which embodies a Venturi device 3 and thermostatic device 4 for the operation of a protective switch 2. The tube I assumed to be of a known liquid cooled type has a coolant inlet 5 and outlet 6. The tube is shown as having an igniter lead l, a cathode power lead 8, and an anode lead 9. Venturi device .3 is connected to outlet 6 of tube I by the conductin pipe H). Thermostatic device 4 is connected to the outlet end of the Venturi device 3 by a short pipe or nipple II and has an outlet l2 which connects to awaste pipe [3.

Venturi device 3 has oppositely disposed conical chambers l4 and I5 which communicate through a cylindrical chamber or throat I6 of smaller diameter. A small cylindrical passage l1 extends from the interior of the throat Hi to the exterior of the Venturi device and is preferably located with respect to said conical chambers so as to communicate with the point of minimum pressurewith respect'toxthe pressure gradient through said conical chambers. A pipe It connects the passage IT to the interior chamber of a bellows type of switch actuator l9 which operates the protective switch 2. The ends of pipe [8 are hermetically sealed to the passage l1 and the chamber within the bellows 19.

Switch 2, which is operated by the bellows I9, is shown diagrammatically to represent any suitable bellows operated switch which moves from its normal position to an actuated position when the pressure within the bellows reaches a predetermined value below atmospheric pressure. The switch 2 has external terminals 26 and 2| for electrical connection with a control circuit for the electron tube I in a well known manner; for example as shown in the aforementioned application.

The thermostatic device 4 has a cylindrical chamber 22 formed by a cylindrical sleeve .23 and circular end plates 24 and 25. A thermostatic bellows 2% is mounted in the chamber 22, by an adjustable connection with the end plate 25. The bellows 26 expands and contracts longitudinally in response to temperature changes, thus causing the left end 21 of said bellows to vary its position with respect to the end 28 of the nipple i Referring to Fig. 2, this shows in cross section a preferred form of thermostatic device 4 and its connection with the nipple II. The end plate '24 is fastened in a fluid tight relationship to :the cylindrical sleeve 23. Plate 24 is drilled and threaded to receive the nipple H whichhas the end 28 projecting a, short distance into the chamber 22. The end plate 25, which islikeWi'se fastened in a fluid tight relationship to the sleeve 23, is drilled and threaded to receive an adjusting screw 29. Adjusting screw 29 has a threaded portion 30 for engagement with a drilled and threaded hole in plate 25. The thermostatic bellows. 26 is mounted on the adjusting screw 29 and is rigidly fastened to it by the bellows mounting disk 3!. An unthreaded extension 32 of the adjusting screw projects into the chamber 37 of bellows 24. The end 33 of the adjusting screw provides a stop which limits thecontractionof the bellows 26. Screwing the adjusting screw 29 i n* wardly or outwardly with respect to the end plate 25 adjusts the space between the end 21 of bellows 26 and the end 28 of the nipple Ii. .Ad-justment of the bellows 26 can be fixed by a lock. nut 34 which fitsover the adjusting screw 29. .onrthe outside of the end plate 25. A brass washer v35 is mounted under the lock nut 34 and bears against a rubber washer or gasket 36. Tightening the locknut 34 prevents movement. of the ad:

justing screw 29 and also effects a fluid seal around the screw by compression of the washers 35 and 36.

Bellows 26 is of corrugated metal construction. Its chamber 37 contains a limited fill of a suitable thermal fluid, and is sealed at the juncture of the adjusting screw 29 and the bellows mounting disk 3|. Bellows 26 expands or contracts due to the vapor pressure developed by its thermal fluid, which changes in accordance with the temperature of the bellows.

When the cooling system is in operation the coolant circulates about the tube I and is discharged through the outlet E. The coolant then passes through the conducting pipe I9 into the Venturi device 3. On entering the Venturi device 3, the coolant will pass through the chamber I4, into the throat I6 and out through the chamber I5. In passing through the chamber I I and the throat I Ii the flowing coolant increases in velocity and decreases in pressure in accordance with a well known law of fluid flow. In passing on through the chamber I5, the flowing coolant decreases in velocity and increases in pressure. The coolant then flows throughthe nipple I I into the chamber 22 of the thermostatic device 9, where it circulates about the bellows 26 and is ultimately discharged to a, sewer through the outlet I2 and the waste pipe I3. By proper design and sizing of the chambers I4 and I5 and the throat I5 pressures considerably below atmospheric can be developed in the throat I6 by a normal circulation of coolant such as to maintain a safe operating temperature in the tube I. When a vacuum is developed in the throat I6 the same will exist inside the bellows I9 by virtue of connection to the throat I6 and contraction of the bellows I9 results. The switch 2 is adjusted to move from its normal position to an actuated position and remains in the latter position by the vacuum induced in the bellows I9 when the coolant flow is suflicient to maintain safe operating temperatures in the tube I. Any decrease in the rate of coolant flow below a given minimum value will permit restoration of atmospheric pressure within the throat I6 and bellows I9 and cause the switch 2 to return to its normal position from the actuated position. When the electronic tube I is operating under normal load conditions with the proper rate of coolant flowing through its cooling system to maintain safe operating temperatures, the Venturi device 3 will respond instantaneously to abnormalities in the rate of coolant flow; the thermostatic device 4 having no effect. However, if the electrical load on tube I is increased above the normal value for'which the rate of coolant flow is adjusted the temperature of the coolant leaving the outlet 6 of tube I and flowing through the cooling system will increase. The increased temperature of the coolant will cause the thermostatic bellows 26 to expand. The end 2? of the bellows will move closer to the end 28 of the nipple -II; This causes restriction in the flow of coolant from the Venturi device 3 into the chamber 22. Restriction of the coolant flow lowers the rate of coolant flow through the Venturi device 3. A lower rate of coolant flow thereby causes an increase in pressure in the throat I6 which in turn aifects the switch 2 as described above.

It will be noted that the action of the thermostatic device 4 in response to abnormal temperature increases in the. coolant leaving the tube I is that of artificially restricting the rate of coolant flow, causing back pressure in the throat I6 the Venturi device 3 thereby causing the bellows actuated switch to respond. Thus the protective switch 2 is made responsive to any abnormal increase in temperature of coolant leaving the tube I as well as to non-operation of or failure of the proper rate of coolant flow.

What I claim as new and desire to secure by Letters Patent is:

1. In combination, an electric device which generates heat as an incident to its operation, a cooling system for said device comp-rising means for confining the flow of a coolant fluid between given points after it leaves said device, said means including means wherein a certain value of vacuum is produced as a function of a normal rate of fluid flow therethrough and means thermally responsive to increase in the temperature of said fluid above a predetermined value to reduce the rate of fluid flow through the second mentioned means whereby the vacuum is reduced, and an electric switch in circuit with said device and having operating means responsive to the vacuum produced in said second mentioned means for retaining said switch in a given position at said certain value of vacuum and affording return of said switch to a normal position to terminate operation of said device when said vacuum is reduced a given amount.

2. In combination, an electric device which generates heat as an incident to its operation, a, cooling system for said device comprising means for confining the flow of a coolant fluid between given points after it leaves said device, said means including a venturi wherein a certain value of vacuum is produced as a function of a normal rate of fluid flow therethrough, means providing a chamber having an inlet and an outlet adapting said chamber to the normal rate of fluid flow therethrough, and further including thermally responsive means subject to contact with the fluid in said chamber, and being responsive to increase in the temperature of said fluid above a predetermined value to constrict the flow of fluid through said chamber for reduction of fluid flow through said Venturi device whereby the vacuum is reduced, and an electric switch in circuit with said device and having operating means connected to said venturi responsive to said certain value of vacuum to retain said switch in a given position and affording return of said switch to a normal position to terminate operation of said device when said vacuum is reduced a given amount.

3. In combination, an electric device which generates heat as an incident to its operation, a cooling system for said device comprising means for confining the flow of a coolant fluid between given points after it leaves said device, said means including a venturi wherein a certain value of. vacuum is produced as a function of a normal rate of fluid flow therethrough, means providing a chamber having an inlet and an outlet adapting said chamber to the normal rate of fluid flow therethrough, and further including a thermally responsive bellows mounted in said chamber and subjected to contact with the fluid in said chamber, said bellows bein expandible in response to increase in temperature of said fluid above a pre determined value to constrict said inlet thereby to reduce the rate of fluid flow through said chamber for reduction of the rate of flow through said venturi whereby the vacuum is reduced, and an electric switch in circuit with said device and having operating means connected to said venturi responsive to said certain value of vacuum to retain said switch in a given position and afiording return of said switch to a normal position to terminate operation of said device when said vacuum is reduced a given amount.

4. In combination, an electron tube of the liquid cooled type, a cooling system for said tube comprising means for confining the flow of a coolant fluid between given points after it leaves said tube, said means including a venturi wherein a certain value of vacuum is produced as a function of a normal rate of fluid flow therethrough, means providing a chamber having an inlet and an outlet adapting said chamber to the normal flow of said fluid, and further including a thermally responsive bellows mounted in said chamber and subjected to contact with the fluid in said chamber, said bellows being expandible in response to increase in temperature of said fluid above a predetermined value to constrict said inlet thereby to reduce the rate of fluid flow through said venturi whereby the vacuum is reduced, and an electric switch in circuit with said tube and havin opcrating means connected to said venturi responsive to said certain value of vacuum to retain said switch in a given position and fiording return of said switch to a normal position to terminate operation of said tube when said vacuum is reduced a given amount.

WILLIAM E. BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

